BAUDREIX Wastewater Treatment Plant, Bourdettes, Nouvelle-Aquitaine, France

BAUDREIX is a wastewater treatment plant located in Bourdettes, a commune in the Pyrénées-Atlantiques department of Nouvelle-Aquitaine, southwestern France. The plant serves a population of around 13,450 people, placing it in the medium agglomeration category under EU classification. As a French facility, BAUDREIX operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires secondary treatment for agglomerations of this size discharging into freshwater. The directive also mandates more stringent treatment if the receiving water body is designated as sensitive. Typical French plants of this scale employ biological treatment with activated sludge or similar technology. The treated effluent is discharged into a local watercourse that ultimately drains into the Gave de Pau river, a major tributary of the Adour river system. The Adour flows into the Bay of Biscay (Atlantic Ocean) near Bayonne. The plant plays a key role in protecting the Gave de Pau and downstream aquatic ecosystems from nutrient pollution and pathogens.

The plant discharges into a tributary of the Gave de Pau river, which flows through the Pyrénées-Atlantiques region before joining the Adour river. The Adour estuary and coastal waters of the Bay of Biscay support diverse marine life, including migratory fish species such as salmon and eels. The watershed is ecologically sensitive due to its proximity to the Pyrenees mountains and agricultural land use, making nutrient removal important for preventing eutrophication downstream.